Airfoils in the nature of vanes and blades are well-known components of turbomachines such as gas turbine engines. Airfoils may be used to direct flow of fluid through the turbomachine and/or impinged upon by fast moving gases to induce rotation of a compressor of the turbomachine or auxiliary equipment. In either case the service environment can be quite harsh, subjecting vanes, blades and the like to extreme temperatures.
A great many different cooling schemes for turbomachine components have been proposed over the years. In one well-known strategy for gas turbine engines a cooling fluid, such as compressed air from the engine's compressor, is conveyed into an interior of the airfoil and then discharged through openings in the airfoil body so as to provide a cooling “film” to cool surfaces of the airfoil. Other strategies attempt to cool the airfoil without generating a film as such but instead circulate the fluid through the airfoil and discharge it downstream near a trailing edge of the airfoil. United States Patent Application Publication No. 2010/0221121 to Liang is one such example.